This is Part 2 of the 6G Tig Pipe Test series. It’s about how to weld the hot pass.
The term “hot pass” is misleading in tig welding. In stick welding open butt root passes using 6010 rod, the hot pass is commonly welded with a bit higher amperage in order to burn out any slag or undercut in the root pass. But in Tig welding, there is no slag and there is usually no undercut to worry about after the root pass is done. So the main goal for the hot pass is to deposit a sound layer of weld with no cold lap or other defects… while not screwing up the root pass in any way.
The main culprit is usually “suck back”!
Suck back is a non standard or kind of a slang term to describe what happens when you melt all the way thru the root pass and “suck it back” to where it is below flush or where the smooth protrusion of the root is disrupted by areas that have been melted and are now uneven.
Suck back is not good. Inspectors and weld test administrators don’t like it. It is something to avoid.
So how do you avoid it?
Here are a few suggestions:
- use about the same amperage as what worked well for the root pass.
- leave the rod in the puddle to help cool it off.
- move quickly across the middle.
If you are preparing to take a 6G test, I wish you luck.